[#2333] Lengthen the audio buffer reduce number of underrun in pulseaudio

sflphone-common/src/audio/pulseaudio/audiostream.cpp

@@ -185,8 +185,8 @@ AudioStream::createStream (pa_context* c)
     // 2048 bytes (1024 int16) is 20 ms at 44100 Hz 
     if (_streamType == PLAYBACK_STREAM) {
         attributes->maxlength = 32000;
-        attributes->tlength = 8192;
-        attributes->prebuf = 2048;
+        attributes->tlength = 16000;
+        attributes->prebuf = 1024;
         attributes->minreq = 512;
         attributes->fragsize = (uint32_t) -1;
         pa_stream_connect_playback( s , NULL , attributes, PA_STREAM_INTERPOLATE_TIMING, &_volume, NULL);
@@ -196,9 +196,9 @@ AudioStream::createStream (pa_context* c)
         // attributes->maxlength = 66500;
         // attributes->fragsize = (uint32_t)-1;
 
-        attributes->maxlength = 16000;
-        attributes->tlength = 8192;
-        attributes->prebuf = 2048;
+        attributes->maxlength = 32000;
+        attributes->tlength = 16000;
+        attributes->prebuf = 1024;
         attributes->minreq = 512;
         attributes->fragsize = (uint32_t) -1;
 

sflphone-common/src/audio/pulseaudio/pulselayer.cpp

@@ -57,8 +57,16 @@ static void stream_moved_callback(pa_stream *s UNUSED, void *userdata UNUSED)
 static void playback_underflow_callback (pa_stream* s,  void* userdata UNUSED)
 {
     _debug ("PulseLayer::Buffer Underflow\n");
+
+    SFLDataFormat* out = (SFLDataFormat*) pa_xmalloc (framesPerBuffer*sizeof(SFLDataFormat));
+    bzero (out, framesPerBuffer*sizeof(SFLDataFormat));
+
+    pa_stream_write (s, out, framesPerBuffer*sizeof(SFLDataFormat), NULL, 0, PA_SEEK_RELATIVE); 
     pa_stream_trigger (s, NULL, NULL);
 
+    pa_xfree (out);
+    
+
 }
 
 
@@ -485,9 +493,9 @@ void PulseLayer::writeToSpeaker (void)
 	    {
 
 		toGet = framesPerBuffer;
-		toPlay = ( (int) (toGet * sizeof (SFLDataFormat)) > framesPerBuffer) ? framesPerBuffer : toGet * sizeof (SFLDataFormat);
+		toPlay = ( (int) (toGet * sizeof (SFLDataFormat)) > framesPerBuffer * sizeof (SFLDataFormat)) ? framesPerBuffer : toGet * sizeof (SFLDataFormat);
 		out = (SFLDataFormat*) pa_xmalloc (toPlay);
-		file_tone->getNext(out, toPlay/2 , 100);
+		file_tone->getNext(out, toPlay/sizeof(SFLDataFormat), 100);
 		pa_stream_write (playback->pulseStream(), out, toPlay, NULL, 0, PA_SEEK_RELATIVE);
 
 		pa_xfree (out);